A novel condensing agent, 3, 3′-carbonylbis [5-phenyl-1, 3, 4-oxadiazole-2 (3H)-thione](3), was readily prepared by the reaction of 5-phenyl-1, 3, 4-oxadiazole-2 (3H)-thione with trichloromethyl chloroformate in benzene. The reagent 3 was found to be very useful for the one-pot or direct preparation of amide, ester, thiol ester, urea, and carbonate under mild conditions. The one-pot or direct polycondensation of several dicarboxylic acids with ...